Condition change alarm system

ABSTRACT

A dual alarm system for monitoring a switch position requiring alarm acknowledgment. When the switch closes, a first alarm goes on steady and a second alarm goes on pulsating. Acknowledgment turns off the first alarm and changes the second alarm from pulsating to steady. When the switch opens, the first alarm again goes on and the second alarm changes to reduced intensity. A second acknowledgment then turns off both alarms.

United States Patent [72] Inventor Logan D. Haddock 2,730,703 l/1956Ross 340/2131 Provo, Utah 2,824,295 2/1958 Zaruba 340/2131 [21] Appl.No.811,306 2,840,804 6/1958 Rodgers 340/2131 [22] Filed Mar. 28, 19693,392,379 7/1968 Thomoson... 340/2131 [45] Patented Nov. 23, 19713.480938 11/1969 Martin 340/2131 [73] Asslgnee United States SteelCorporation Primary E mminer Thomas B. Habecker Attorney-Rea C. Helm[54] CONDITION CHANGE ALARM SYSTEM 3Clalms l Drawmg ABSTRACT: A dualalarm system for monitoring a switch [52] U.S.Cl 340/2l3.l, positionrequiring alarm acknowledgment. When the switch 307/243 closes. a firstalarm goes on steady and a second alarm goes on [51] 1nt.Cl ..G08bl9/00,pulsating. Acknowledgment turns off the first alarm and G08b 29/00changes the second alarm from pulsating to steady. When the [50] Fieldof Search 340/2131 switch opens, the first alarm again goes on and thesecond alarm changes to reduced intensity. A second [56] ReferencesC'ted acknowledgment then turns off both alarms.

UNITED STATES PATENTS 2.730.704 1/1956 Warren 340/2131 24a 24b EYCE'SS6A; j twa 24 T l g l x I l I 26 wsuAL l Aw/BLE I ALARM l ALARM l i 1 a II T I I FM 30 10 l 32-5! 38 4 I 06 l 40! I SOURCE I [a as l 2 so C, l 20l 42 I lit l L T i cow/now 54 55 ALA/m 34 7557 SWITCH 7 sw/m/ l 50 T52 Tl l l INSUFF/C/ENT GAS "82' PATENTEUunv 23 \an INVENTOR LOGAN 0. HADDOCKBr 2% 4 M Allorney CONDITION CHANGE ALARM SYSTEM This invention relatesto an alarm system activated by a changed condition and, moreparticularly, to such a system that requires acknowledgement each timean alarm indicates a change in condition.

Gas from blast furnaces is commonly used in steel mills to firepowerhouse boilers. Since the production of gas fluctuates more than thedemand, holders, such as piston-operated steel tanks, are used on a gasline to smooth out the fluctuations. Because a holder may be damaged ifit contains too much or too little gas, warning devices are provided toindicate either abnormal condition so that a gas operator may take thenecessary corrective action.

However, in alarm systems with which I am familiar and particularlywhere the operator has considerable other responsibilities and duties,the operator may miss a return of the abnormal condition to normal or hemay not be sure of the status of a prior required acknowledgment of anabnormal condition signal. This can be aggravated with multiplecondition alarm systems.

It is, therefore, an object of my invention to provide an alarm systemfor changes in condition with audio and visual indicators where oneindicator shows acknowledgment.

Another object of my invention is a system where an indicator shows thestatus of the condition and the status of an acknowledgment.

Still another object is to provide such a system where more than one setof conditions may be monitored in one indicator.

These and other objects will become more apparent after referring to thefollowing specification and drawing, in which:

The single FIGURE is a schematic diagram of my invention.

Referring now to the drawing, reference numeral 2 indicates a conditionalarm switch which, for example, may close when a gas holder in the gasline between a blast furnace and a boiler house contains too much gas,thereby requiring corrective action by an operator. One side of switch 2is connected to the negative side of a direct-current source 4. Thepositive side of source 4 is connected to an audible alarm 6 such as ahorn or bell and to a visual alarm 8 which is an incandescent lamp ashereinafter described. A first silicon controlled rectifier 10 has itsanode connected to lamp 8, its cathode connected to switch 2 and itsgate connected to switch 2 through a resistance 12. A second siliconcontrolled rectifier 14 has its anode connected to lamp 8 through aresistance 16, its cathode connected to the negative side of source 4, aresistance 18 connected between its gate and cathode, and a capacitance20 connected between its gate and switch 2.

A capacitor 22 is connected from the anode of rectifier 14 to a pushbutton 24a, resistance 26, and a capacitor 28. Push button 24a is alsoconnected to the negative side of source 4. Resistance 26 is alsoconnected to a push button 24b and the positive side of source 4. Pushbutton 24b is also connected to the gate of rectifier 10 through aresistance 30. Push buttons 24a and 24b are connected to operatetogether as an acknowledge switch 24. A diode 32 and a test switch 34are connected in series between lamp 8 and the negative side of source4.

A transistor 36 has its emitter connected to switch 2, its collectorconnected to lamp 8 through a diode 38 and its base connected to thecollector of a transistor 40 through a resistance 42. The emitter oftransistor 40 is connected to the positive side of source 4 and the baseof transistor 40 is connected to switch 2 through a resistance 44 and tothe collector of transistor 36 through a resistance 46 and a capacitor48.

Alarm 6 is connected to capacitor 28 and the anode of a siliconcontrolled rectifier 50. The cathode of rectifier 50 is connected to thenegative side of source 4 through a diode 52 and to a capacitor 54through a diode 56, and its gate is connected to the negative side ofsource 4 through a resistance 58 and to capacitor 54 through a diode 60.Capacitor 54 is also connected to switch 2.

The parts of my alarm system for excess gas monitored by switch 2 areenclosed in block 62. Block 62' is an alarm system with the samecomponents as block 62 except that the condition alarm switch isconnected to close when there is insufiicient gas in the holder.

To activate my alarm system, it is first assumed that the system isdeenergized and all capacitors are discharged. As soon as source 4 isenergized, capacitor 54 is charged from source 4 through lamp 8, diode38, capacitor 48, resistance 46, resistance 44, diode 60 and resistance58 to source 4. Charging capacitor 54 results in a voltage spike ofsufficient magnitude at the gate of rectifier 50 to turn rectifier 50on. This activates audible alarm 6 and charges capacitor 28 throughresistance 26, rectifier 50 and diode 52. The operator must thenmomentarily press reset button 24 to turn alarm 6 off. Closing contacts24a discharges capacitor 28 through rectifier 50 and diode 52 whichturns rectifier 50 and alarm 6 off while capacitor 54 remains charged.The alarm system is now ready to operate.

Assume now that there is an excess of gas which closes switch 2. Thisactivates transistors 36 and 40 which together with capacitor 48 andresistances 42, 44 and 46 form a conventional oscillator. Transistor 36is thus timed on and off at about one second intervals, turning lamp 8on and off through diode 38. The positive charge on capacitor 54 istransferred to the gate of rectifier 50 driving the cathode of rectifier50 negative with respect to the gate and turning rectifier 50 on. Thisalso energizes audible alarm 6. Capacitor 28 is now charged throughresistance 26, rectifier 50 and diode 52. The operator is now alerted tothe changed condition by the audible alarm 6 and a flashing visual alarm8.

The operator acknowledges the changed condition by momentarily closingacknowledge switch 24. Closing of contact 24a discharges capacitor 28through rectifier 50 and diode 52 which turns off rectifier 50 and theaudible alarm 6. Closing of contact 24b provides a positive potential tothe gate of rectifier 10 from voltage divider resistances l2 and 30turning on rectifier 10. This shunts out the oscillator circuit changinglamp 8 to steady on. So long as switch 2 is closed, lamp 8 will remainon to remind the operator of the acknowledged changed condition.

When the condition again changes, such as a return to normal gas level,switch 2 will open. This turns rectifier 10 off. Capacitor 20 thencharges through resistance 18, resistance 44, resistance 46, capacitor48, diode 38 and lamp 8. This turns on rectifier 14 which energizes lamp8 at half brilliance through voltage dropping resistance 16. Capacitor22 re then charges through resistance 26. Capacitor 54 recharges. Theresultant voltage spike turns rectifier 50 on. Alarm 6 then turns onrecharging capacitor 28 and alerts the operator that the condition hasreturned to normal.

The operator acknowledges this by momentarily closing acknowledge 24 asecond time. Closing of contacts 24discharges capacitor 28 throughrectifier 50 and diode 52 which turns off rectifier 50 and the audiblealarm 6. Closing of contact 24also discharges capacitor 22 throughrectifier l4 turning off rectifier l4 and lamp 8. Capacitor 54 nowrecharges. The alarm system is now ready to receive another change incondition. Capacitor 20 is discharged through resistance 18 as soon asswitch 2 is closed.

Test switch 34 and diode 32 are provided to test visual alarm lamp 8without disturbing the rest of the circuit.

The second condition alarm system 62 functions in the same manner as thefirst system 62. Any number of systems may be used to turn off audiblealarm 6, each one of which may turn off the audible alarm withoutaffecting the operation of the other systems.

While alarms 8 and 6 are shown as visible and audible, respectively, itis obvious that these alarms could be other than the type indicatedprovided the circuit requirements for charging and discharging thecapacitors are fulfilled.

While one embodiment of my invention has been described, it will beapparent that other adaptations and modifications may be made.

I claim:

I. An alarm system requiring acknowledgment for each change in positionof a condition responsive switch comprising a condition responsiveswitch having an open and a closed position, a power source, a firstalarm means, first means responsive to a change in position of saidswitch for energizing said first alarm means by said power source, asecond alarm means having a first, a second, a third and a fourthindicating conditions, second means responsive to the closing of saidswitch for energizing said second alarm means in said second conditionby said power source, third means responsive to the opening of saidswitch for energizing said second alarm means in said fourth conditionby said power source, said switch opening also deenergizing said secondresponsive means, acknowledgment means for deenergizing said firstresponsive means and said first alarm means, said acknowledgment meansalso actuating means for shunting said second responsive means to changesaid second alarm means from said second condition to said thirdcondition when said switch is closed and said acknowledgment means alsodeenergizing said third responsive means and said shunting means tochange said second alarm means from said fourth condition to said firstcondition when said switch is open.

2. An alarm system according to claim I in which said first alarm meansis a horn and said second alarm means is an incandescent lamp which isoff in said first condition, flashing on and off in said secondcondition, on at full intensity in said third condition and on a reducedintensity in said fourth condition 3. An alarm system according to claim1 which includes a plurality of condition responsive switches eachhaving an open and a closed position, a plurality of second alarm means,second responsive means, third responsive means and acknowledgment meanseach associated with one of said switches and means connecting saidplurality of switches, second alarm means, second responsive means,third responsive means and acknowledgment means to said first alarmmeans and said first responsive means whereby each of said switches andits associated acknowledgement means will operate said first alarm meansand its associated second alarm means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,623048 Dated November 23, 1971 Invent0 Logan D. Haddock It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 2, line 13, cancel "press reset button" and insert closeacknowledge switch line 46, after "22" delete "re"; line 52, after"acknowledge" insert switch line 53, "24" should read 24a line 55, "24"should read Signed and sealed this 14th day of November 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR.

ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents DRM PO-IDSO(10-69) USCOMM-DC BO37B-F'69 9 U 5 GOVERNMENT PRINTING OFFICE 19903662134 Liir

1. An alarm system requiring acknowledgment for each change in positionof a condition responsive switch comprising a condition responsiveswitch having an open and a closed position, a power source, a firstalarm means, first means responsive to a change in position of saidswitch for energizing said first alarm means by said power source, asecond alarm means having a first, a second, a third and a fourthindicating conditions, second means responsive to the closing of saidswitch for energizing said second alarm means in said second conditionby said power source, third means responsive to the opening of saidswitch for energizing said second alarm means in said fourth conditionby said power source, said switch opening also deenergizing said secondresponsive means, acknowledgment means for deenergizing said firstresponsive means and said first alarm means, said acknowledgment meansalso actuating means for shunting said second responsive means to changesaid second alarm means from said second condition to said thirdcondition when said switch is closed and said acknowledgment means alsodeenergizing said third responsive means and said shunting means tochange said second alarm means from said fourth condition to said firstcondition when said switch is open.
 2. An alarm system according toclaim 1 in which said first alarm means is a horn and said second alarmmeans is an incandescent lamp which is off in said first condition,flashing on and off in said second condition, on at full intensity insaid third condition and on a reduced intensity in said fourth condition3. An alarm system according to claim 1 which includes a plurality ofcondition responsive switches each having an open and a closed position,a plurality of second alarm means, second responsive means, thirdresponsive means and acknowledgment means each associated with one ofsaid switches and means connecting said plurality of switches, secondalarm means, second responsive means, third responsive means andacknowledgment means to said first alarm means and said first responsivemeans whereby each of said switches and its associated acknowledgementmeans will operate said first alarm means and its associated secondalarm means.